Before securing them in place by adding the outer hoop and tightening:

The lengths of thread attached to each feather could then be pulled to vary the length until I was
happy with the arrangement:

Secure each length with a knot and trim the excess to neaten the finish:

...before your dreamcatcher is ready to hang:

Simple as that - a few wraps of decorative thread and some feathers is all you need - vary the look by adding beads, charms or embellishments to the hoop and thread and you can create a variety of feathers using shop made or cut your own from decorative paper or fabric.